5 files changed, 41 insertions, 0 deletions
diff --git a/gcc/rust/ast/rust-macro.cc b/gcc/rust/ast/rust-macro.cc
index 0b21d42..b558969 100644
--- a/gcc/rust/ast/rust-macro.cc
+++ b/gcc/rust/ast/rust-macro.cc
@@ -42,6 +42,9 @@ builtin_macro_from_string (const std::string &identifier)
   if (identifier == "include_str")
     return BuiltinMacro::IncludeStr;
 
+  if (identifier == "stringify")
+    return BuiltinMacro::Stringify;
+
   if (identifier == "compile_error")
     return BuiltinMacro::CompileError;
 
diff --git a/gcc/rust/ast/rust-macro.h b/gcc/rust/ast/rust-macro.h
index 0e6b8e3..2ea42e4 100644
--- a/gcc/rust/ast/rust-macro.h
+++ b/gcc/rust/ast/rust-macro.h
@@ -589,6 +589,7 @@ enum class BuiltinMacro
   Column,
   IncludeBytes,
   IncludeStr,
+  Stringify,
   CompileError,
   Concat,
   Env,
diff --git a/gcc/rust/expand/rust-macro-builtins.cc b/gcc/rust/expand/rust-macro-builtins.cc
index 2bd8120..2c6856a 100644
--- a/gcc/rust/expand/rust-macro-builtins.cc
+++ b/gcc/rust/expand/rust-macro-builtins.cc
@@ -58,6 +58,9 @@ make_macro_path_str (AST::BuiltinMacro kind)
     case AST::BuiltinMacro::IncludeStr:
       path_str = "include_str";
       break;
+    case AST::BuiltinMacro::Stringify:
+      path_str = "stringify";
+      break;
     case AST::BuiltinMacro::CompileError:
       path_str = "compile_error";
       break;
@@ -845,4 +848,34 @@ MacroBuiltin::line_handler (Location invoc_locus, AST::MacroInvocData &)
   return AST::Fragment ({line_no}, std::move (tok));
 }
 
+AST::Fragment
+MacroBuiltin::stringify_handler (Location invoc_locus,
+				 AST::MacroInvocData &invoc)
+{
+  std::string content;
+  auto invoc_token_tree = invoc.get_delim_tok_tree ();
+  auto tokens = invoc_token_tree.to_token_stream ();
+
+  // Tokens stream includes the first and last delimiter
+  // which we need to skip.
+  for (auto token = tokens.cbegin () + 1; token < tokens.cend () - 1; token++)
+    {
+      // Rust stringify format has no garantees but the reference compiler
+      // removes spaces before some tokens depending on the lexer's behavior,
+      // let's mimick some of those behaviors.
+      auto token_id = (*token)->get_id ();
+      if (token_id != RIGHT_PAREN && token_id != EXCLAM
+	  && token != tokens.cbegin () + 1)
+	{
+	  content.push_back (' ');
+	}
+      content += (*token)->as_string ();
+    }
+
+  auto node = AST::SingleASTNode (make_string (invoc_locus, content));
+  auto token
+    = make_token (Token::make_string (invoc_locus, std::move (content)));
+  return AST::Fragment ({node}, std::move (token));
+} // namespace Rust
+
 } // namespace Rust
diff --git a/gcc/rust/expand/rust-macro-builtins.h b/gcc/rust/expand/rust-macro-builtins.h
index 0cab9b1..bd4f1f9 100644
--- a/gcc/rust/expand/rust-macro-builtins.h
+++ b/gcc/rust/expand/rust-macro-builtins.h
@@ -79,6 +79,9 @@ public:
   static AST::Fragment include_str_handler (Location invoc_locus,
 					    AST::MacroInvocData &invoc);
 
+  static AST::Fragment stringify_handler (Location invoc_locus,
+					  AST::MacroInvocData &invoc);
+
   static AST::Fragment compile_error_handler (Location invoc_locus,
 					      AST::MacroInvocData &invoc);
 
diff --git a/gcc/rust/util/rust-hir-map.cc b/gcc/rust/util/rust-hir-map.cc
index f78ef93..535731b 100644
--- a/gcc/rust/util/rust-hir-map.cc
+++ b/gcc/rust/util/rust-hir-map.cc
@@ -856,6 +856,7 @@ Mappings::insert_macro_def (AST::MacroRulesDefinition *macro)
       {"column", MacroBuiltin::column_handler},
       {"include_bytes", MacroBuiltin::include_bytes_handler},
       {"include_str", MacroBuiltin::include_str_handler},
+      {"stringify", MacroBuiltin::stringify_handler},
       {"compile_error", MacroBuiltin::compile_error_handler},
       {"concat", MacroBuiltin::concat_handler},
       {"env", MacroBuiltin::env_handler},